Solar concentrator array with grouped adjustable elements

ABSTRACT

A tracking heliostat array comprises a plurality of optical elements. The tracking heliostat array further comprises a frame separated from the optical elements. Each of the optical elements has an orientation with respect to the frame. The tracking heliostat array further comprises a plurality of supports coupled to at least one of the optical elements. The tracking heliostat array further comprises a turnbuckle coupled to at least one of the supports and to the frame. Rotation of the turnbuckle causes the corresponding support to be displaced relative to the frame. The orientation of the optical element relative to the frame is adjustable. The tracking heliostat array further comprises a traveling actuator configured to rotate at least one of the turnbuckles. The tracking heliostat array further comprises a positioning mechanism supporting the traveling actuator. The positioning mechanism is configured to move the traveling actuator from a first selected turnbuckle to a second selected turnbuckle.

PRIORITY APPLICATION

This application claims the benefit of U.S. Provisional Application60/486,879, filed 10 Jul. 2003, the entire disclosure of which is herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to solar concentrators, and morespecifically to an array of solar concentrators capable of trackingmovement of the sun.

BACKGROUND OF THE INVENTION

Many solar concentrators comprise a single optical element, such as asingle lens, mirror, or reflector. Examples of such concentratorsinclude dish and trough concentrators. Other solar concentratorscomprise an array of optical elements that are individually adjustableto track the position of the sun in the sky. One type of arrayedconcentrator is the “heliostat array”. In a heliostat array, a field ofreflective optical elements concentrates solar energy on a collectorhaving dimensions that are small compared to the dimensions of thearray. The orientation of the optical elements in a heliostat array canbe individually adjustable, thereby allowing the focal point of thearray to remain on the collector over the course of a day and duringdifferent seasons. Such an arrangement is often referred to as a“tracking” heliostat array.

In a conventional tracking heliostat array, configuring each opticalelement to be individually movable typically requires a large amount ofexpensive motorized equipment. For example, in one conventionalconfiguration, two motors are used to adjust the orientation of eachelement in the tracking heliostat array. Thus, using this configuration,a tracking heliostat array comprising a 10×10 array of mirrors uses 200motors to adjust the orientation of the mirrors. In addition to causingthe array to be undesirably expensive, this large amount of motorizedequipment results in an array that is relatively heavy, which isparticularly disadvantageous for applications where weight is asignificant factor, such as for rooftop mounted applications.

SUMMARY OF THE INVENTION

Based on the foregoing, an improved tracking heliostat array has beendeveloped. In an example embodiment, a relatively small number of motorscan be used to adjust the orientation of a relatively greater number ofindividual optical elements in the array. By using a single group ofmotors to adjust the orientation of several different optical elements,the number of motors used can optionally be substantially independent ofthe number of optical elements in the array. This advantageously reducesthe cost, complexity and weight of the array, thereby enabling trackingheliostat arrays to be used in small-scale applications and/or weightsensitive applications, such as individual rooftop mounted residentialsystems, as well as large-scale applications.

In one embodiment of the present invention, a tracking heliostat arraycomprises a plurality of optical elements. The tracking heliostat arrayfurther comprises a frame separated from the optical elements. Each ofthe optical elements has an orientation with respect to the frame. Thetracking heliostat array further comprises a plurality of supportscoupled to at least one of the optical elements. The tracking heliostatarray further comprises a turnbuckle coupled to at least one of thesupports and to the frame. Rotation of the turnbuckle causes thecorresponding support to be displaced relative to the frame. Theorientation of the optical element relative to the frame is adjustable.The tracking heliostat array further comprises a traveling actuatorconfigured to rotate at least one of the turnbuckles. The trackingheliostat array further comprises a positioning mechanism supporting thetraveling actuator. The positioning mechanism is configured to move thetraveling actuator from a first selected turnbuckle to a second selectedturn buckle.

According to another embodiment of the present invention, a concentratorapparatus comprises a plurality of optical elements positionable toconcentrate light. The concentrator apparatus further comprises asupport structure separated from the optical elements. Each of theoptical elements has an adjustable orientation with respect to thesupport structure. The concentrator apparatus further comprises aplurality of adjustment mechanisms. Actuation of a selected. adjustmentmechanism changes the orientation of an optical element corresponding tothe selected adjustment mechanism. The concentrator apparatus furthercomprises a traveling actuator configured to sequentially actuate aplurality of the selected adjustment mechanisms.

According to another embodiment of the present invention, a method ofconcentrating solar radiation on a collector using a plurality ofreflectors comprises moving a traveling actuator to a first selected oneof the plurality of reflectors. The method further comprises rotating afirst turnbuckle corresponding to the first selected reflector, therebychanging an orientation of the first selected reflector in a firstplane. The method further comprises rotating a second turnbucklecorresponding to the first selected reflector, thereby changing anorientation of the first selected reflector in a second plane orthogonalto the first plane. The method further comprises moving the travelingactuator to a second selected one of the plurality of reflectors. Themethod further comprises rotating a third turnbuckle corresponding tothe second selected reflector, thereby changing an orientation of thesecond selected reflector in the first plane. The method furthercomprises rotating a fourth turnbuckle corresponding to the secondselected reflector, thereby changing an orientation of the secondselected reflector in the second plane.

According to another embodiment of the present invention, a method ofconcentrating optical energy onto a collector comprises positioning atraveling actuator to engage a first optical element. The method furthercomprises moving the first optical element from a first orientation to asecond orientation using the traveling actuator. The first opticalelement reflects more optical energy onto a collector when positioned inthe second orientation as compared to the first orientation. The methodfurther comprises positioning the traveling actuator to engage a secondoptical element. The method further comprises moving the second opticalelement from a first orientation to a second orientation using thetraveling actuator. The second optical element reflects more opticalenergy onto the collector when positioned in the second orientation ascompared to the first orientation.

According to another embodiment of the present invention, a concentratorsystem comprises a first optical element tiltable with respect to atleast one axis via a first adjustment structure. The system furthercomprises a second optical element tiltable with respect to at least oneaxis via a second adjustment structure. The second optical element istiltable independently of the first optical element. The system furthercomprises a traveling actuator configured to travel to engage the firstadjustment structure to tilt the first optical element to a firstdesired orientation. The traveling actuator is further configured totravel to engage the second adjustment structure to tilt the secondoptical element to a second desired orientation.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the improved tracking heliostat array areillustrated in the accompanying drawings, which are for illustrativepurposes only. The drawings comprise the following figures, in whichlike numerals indicate like parts.

FIG. 1 is a perspective view of an exemplary tracking heliostat arrayhaving ninety-six reflectors.

FIG. 2 is a perspective view of another exemplary tracking heliostatarray having four reflectors.

FIG. 3 is a perspective view of an exemplary adjustable reflectorsupport mechanism.

FIG. 4 is a schematic illustration of an exemplary traveling actuator.

FIG. 5 is a schematic illustration of an exemplary mechanism forsupporting a traveling actuator under a rectangular heliostat array.

FIG. 6 is a schematic illustration of an exemplary mechanism forsupporting a traveling actuator under a circular heliostat array.

FIG. 7A is a schematic illustration of an exemplary system forcontrolling a tracking heliostat array.

FIG. 7B is a flowchart illustrating an exemplary method of operating afeedback system with a tracking heliostat array.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As described herein, an improved heliostat or solar concentrator arrayhaving individually adjustable optical elements has been developed. Byusing a common set of motors to adjust the orientation of individualoptical elements serially, sequentially, or in other desired order,fewer overall motors are required as compared to an array havingdedicated motors associated with each optical element. Consequently, theimproved tracking heliostat arrays disclosed herein can be lessexpensive, more reliable, and lighter than many conventional trackingheliostat arrays.

Heliostat arrays reflect solar energy from the sun or other light sourceonto a collector or receiver, where it is generally converted to anotherform of energy. The solar energy is reflected by “optical elements,”which can include planar mirrors, concave mirrors, lenses, reflectors,other devices capable of reflecting or focusing light, and/or acombination of the foregoing. The optical elements are optionallyenclosed within a clear cover, such as a plastic cover, to protect thearray from environmental damage or dirt. As used herein, the “collector”refers generally to a device configured to receive solar energyreflected from the heliostat array and to convert the received solarenergy to another form of energy.

Certain collectors, such as photovoltaic cells and Stirling enginescombined with a generator, convert the received solar energy intoelectric energy, which can be in the form of a voltage potential with anassociated available current. Other collectors convert the receivedsolar energy into other forms of energy, such as thermal energy and/ormechanical energy. For example, a Stirling engine can be included in thecollector. The Stirling engine converts thermal energy or a temperaturedifferential, such as that resulting from focused solar energy, tomovement. An example Stirling engine can include a displacer piston thatmoves enclosed air back and forth between cold and hot reservoirs. Aregenerator, which can be in the form of a wire mesh or the displacerpiston itself, is optionally positioned between the hot and coldreservoirs. In the hot reservoir the air expands and pushes a powerpiston, producing work and displacing the air to the cold reservoir. Theair contracts in the cold reservoir, thereby “pulling” the power piston.If a regenerator is used, then as the air cycles between the hot andcold reservoirs, the heat is transferred to and from the regenerator. Byway of further example, a frying pan can be used to convert solar energyreceived from a heliostat array into thermal energy, which can then beused to cook food that is placed in the frying pan.

An exemplary heliostat array is illustrated in FIG. 1. This heliostatarray 100 includes a plurality of optical elements 110 which are mountedto an optional underlying support frame 120. The support frame 120includes a mount 122 configured to support a collector 124 in a positionto receive solar energy reflected from the optical elements 110. Themount 122 is optionally pivotable or otherwise moveable so as toposition the collector 124 in a desired position. The heliostat array100 can be mounted in a location that is exposed to sunlight, such as arooftop or the ground, and the particular configuration of the examplesupport frame 120 can be adjusted based on the mounting location. Asillustrated in FIG. 1, the heliostat array 100 can be mounted in aninclined orientation so as to more directly face the sun, such as on aninclined south-facing rooftop. Optionally, the inclination angle can bevaried by having the inclined portion pivot relative to the bottom ofthe frame 120, wherein the position can be locked via pins, bolts,clamps, and so on.

To increase the amount of solar energy reflected onto the collector, theorientation of the optical elements comprising the heliostat array canbe adjusted. For example, certain heliostat arrays are configured tochange the orientation of the optical elements over the course of a dayor a year to increase the amount of solar energy reflected onto thecollector. Heliostat arrays having adjustable optical elements are oftenreferred to as “tracking” heliostat arrays. In certain conventionalembodiments, one or more motors are fixedly coupled to each opticalelement in the array, thereby allowing the orientation of each elementto be individually adjusted.

An improved tracking heliostat array system has been developed. In thisimproved system, the optical elements are individually adjustable, butone or more motors are shared by the optical elements, and so dedicatedmotors for adjusting each optical element are not required. For example,one or more traveling actuators can be used to sequentially orseparately adjust the orientation of individual optical elementscomprising the array. FIG. 2 illustrates an exemplary 2×2 array ofoptical elements 110 that are individually adjustable using travelingactuators as described in greater detail herein. For clarity, theexample system illustrated in FIG. 2 includes only four opticalelements; the traveling actuator system disclosed herein can also beused with larger or smaller heliostat arrays, including arrays that arecircular, linear, rectangular, or irregular in general shape.

Still referring to FIG. 2, the optical elements 110 are mounted orcoupled to a plurality of support assemblies 130. An exemplary supportassembly 130 is illustrated in FIG. 3. This exemplary support assembly130 includes a plurality of element mounts 132. The element mounts 132are configured to be secured to the optical element 110, such as with anadhesive, a hook-and-loop fastener, a screw, a bolt, a magnet, a snap, apin, or other appropriate attachment mechanism.

Opposite the optical element 110, the element mounts 132 are attached tohinge 134. The hinge 134 allows the element mounts 132 to pivot withrespect to adjustable rods 136 and fixed rod 138, as illustrated in FIG.3. The fixed rod 138 is secured to support base 140. The adjustable rods136 are threaded into turnbuckles 142, which include a link with screwthreads at one end or both ends thereof. The turnbuckles 142 areconfigured such that rotation of the turnbuckle 142 causes theadjustable rods 136 to be threaded through the turnbuckle threads,thereby causing the corresponding element mounts 132 to be raised(extended) or lowered (retracted) relative to the support base 140 tothereby orient the optical element 110 by pivotably pushing or pullingthe corresponding optical element. The turnbuckles 142 are mounted topivotable hinges 144, which are connected through the support base 140to gear 146. In one embodiment, the gear 146 is a four-pronged ortoothed pinwheel, although the gear 146 can include greater or fewerteeth.

Thus, rotating the gear 146 causes the corresponding pivotable hinge 144and turnbuckle 142 to rotate. This causes the corresponding adjustablerod 136 to be threaded through the turnbuckle 142, and thereby causesthe corresponding element mount 132 to move up or down relative to thesupport base 140, depending on the direction that the gear 146 isrotated. Other embodiments can use other types of support and/orpositioning assemblies. For example, pneumatic or magnetic supportand/or positioning assemblies can be used.

Thus, the exemplary support assembly 130 illustrated in FIG. 3 allowsthe orientation of the optical elements 110 mounted thereto to beadjusted by rotating the gears 146. As the optical element 110 isreoriented, the hinge 134 moves to accommodate the optical element withrespect to the fixed rod 138. While the exemplary embodiment illustratedin FIG. 3 includes two adjustable rods 136 and one fixed rod 138, otherembodiments include other combinations of fixed and adjustable rods,depending on the number of degrees of freedom the optical element 110 isto have. For example, in other embodiments the support assembly 130includes one adjustable rod and one fixed rod, one adjustable rod andtwo fixed rods or three adjustable rods. Other combinations can be usedin other embodiments, including combinations with more than three totalrods.

Referring again to FIG. 2, in an exemplary embodiment the supportassemblies 130 are mounted to mounting bracket 150. Optionally, thesupport assemblies 130 are removably mounted to the mounting bracket150, thereby allowing their position on the mounting bracket 150 to beadjustable, and also allowing individual support assemblies 130 to beindependently removed if repair or replacement becomes necessary.Additionally, in other embodiments, more or fewer than four supportassemblies can be mounted to the mounting bracket; for example, in oneembodiment an 8×12 array of support assemblies are mounted to themounting bracket. The mounting bracket optionally includes feet 152(illustrated in FIG. 2) which can be used to secure the mounting bracketto the support frame 120 (illustrated in FIG. 1).

The foregoing describes a tracking heliostat array having a plurality ofoptical elements 110 mounted to a support frame 120. The orientation ofa selected optical element 110 can be adjusted by turning one or moregears 146 associated with the selected optical element 110.

In an exemplary embodiment of the tracking heliostat array disclosedherein, a traveling actuator is used to engage and rotate the gears 146of the support assemblies 130 or otherwise cause the optical element tobe moved or rotated to the desired orientation. An exemplary embodimentof the traveling actuator 160 is illustrated in FIG. 4. The travelingactuator 160 comprises a base 162 which houses a motor 168, such as asmall electric AC or DC motor. The traveling actuator further comprisesa drive gear 164 coupled to a motor drive shaft 166. In suchembodiments, the motor is configured to separately move the motor driveshaft 166 in two dimensions. First, the motor is configured to move themotor drive shaft 166 linearly, as indicated by arrows L in FIG. 4. Thismotion can be used to engage and disengage the drive gear 164 with oneof the support assembly gears 146 described herein. Second, the motor isconfigured to rotate the motor drive shaft 166, as indicated by arrows Rin FIG. 4. Once the drive gear 164 is engaged with one of the supportassembly gears 146, the rotational motion can be used to rotate thesupport assembly gear 146.

Therefore, the traveling actuator 160 can be used to rotate one of thesupport assembly gears 146. In a modified embodiment, the travelingactuator 160 can be configured to engage and disengage the supportassembly using an electromagnet to rotate the turnbuckle adjustable rods136. In such embodiments, the traveling actuator motor can optionally beconfigured to move the motor drive shaft 166 only rotationally, therebysimplifying the design even further. In other modified embodiments, thetraveling actuator 160 can be configured to rotate the pivotable hinges144 and turnbuckles 142 using a screw-screwdriver arrangement, aplug-receptacle arrangement, a key-key receptacle arrangement, or otherappropriate arrangements.

In the illustrated example, the traveling actuator 160 can actuate thegears 146 of the plurality of support assemblies 130 in the heliostatarray. To position the traveling actuator 160 adjacent to the gear 146to be actuated, the traveling actuator 160 is mounted on a positioningstage 170, an exemplary embodiment of which is illustrated in FIG. 5.The positioning stage 170 is optionally mounted substantially parallelto a plane defined by the array of optical elements or the support frame120. The positioning stage 170 is configured to allow the travelingactuator 160 to be positioned adjacent to the gear 146 to be rotated. Inan exemplary embodiment; the positioning stage 170 includes a firstmotor 172 configured to move the traveling actuator 160 along a firstlinear track 174, and a second motor 176 configured to move the firstlinear track 174 along at least one second linear track 178. In thisexemplary embodiment, the first motor 172 moves the traveling actuator160 in the ±x direction, and the second motor 176 moves the travelingactuator 160 in the ±y direction.

In an exemplary embodiment, the positioning stage 170 illustrated inFIG. 5 is mounted to the support frame 120 using mounting hardware 179.Placing the positioning stage 170 opposite the mounting bracket 150 fromthe optical elements 110 allows the traveling actuator to engage thesupport assembly gears 146, as described herein. This configurationadvantageously allows the traveling actuator 160 to reach the gears 146associated with the support assemblies 130 that comprise the heliostatarray.

In this exemplary configuration, the number of motors required to moveand actuate the traveling actuator 160 is substantially independent ofthe number of optical elements in the heliostat array. For example, thesame number of motors used to adjust the optical elements in the 2×2heliostat array illustrated in FIG. 2 can be used to adjust the opticalelements in the 8×12 heliostat array illustrated in FIG. 1. This shouldbe distinguished from many conventional tracking heliostat arrays,wherein the number of motors required to adjust the optical elementsvaries in direct proportion with the number of optical elements presentin the array.

Although FIG. 5 illustrates that the positioning stage 170 can beconfigured to move the traveling actuator 160 to a particular locationusing orthogonal linear movements, other configurations can beimplemented in other embodiments. For example, FIG. 6 illustrates aradial positioning stage 180 configured to move the traveling actuator160 to a particular location using angular and radial movements. Thisconfiguration is particularly useful when the optical elements 110 arearrayed in a circular arrangement.

In the exemplary embodiment illustrated in FIG. 6, a first motor 182 isconfigured to rotate arm 184 around a central housing 185. A secondmotor 186 is configured to move the traveling actuator 160 linearlyalong the arm 184. That is, the first motor 182 provides rotationalmovement R, whereas the second motor 186 provides linear movement L. Thearm 184 is optionally supported by supplementary support 188, which is awheel in an exemplary embodiment. In such a configuration, the centralhousing 185 optionally provides a mounting location for the collector124 (not shown).

In a modified embodiment, more than one traveling actuator is used toadjust the optical elements. For example, in the rotary embodimentillustrated in FIG. 6, the first motor 172 can be configured to driveadditional arms supporting additional traveling actuators. Or, the arm184 can be configured to support more than one traveling actuator. Asanother example, in the linear embodiment illustrated in FIG. 5, thesecond linear track 178 can be configured to support additional firstlinear tracks supporting additional traveling actuators. Or, the firstlinear track 174 can be configured to support more than one travelingactuator.

The traveling actuators can be controlled and positioned by acontroller, which can include a state machine, an embedded processorexecuting program instructions, and/or a general purpose computerexecuting program instructions. A schematic illustration of an exemplarycontrol system is provided in FIG. 7A. The controller can be coupled tothe traveling actuators via a motor interface circuit. The controllercan further include position information, such as x-y locationinformation or angle and radial information, for the support mechanisms.Using this position information, the controller will move the travelingactuators to accordingly engage the support mechanisms. In addition oralternatively, the traveling actuators can include sensors, such asoptical, radiofrequency, or magnetic sensors that sense a correspondingbar code, radiofrequency identifier tag, or magnetic strip. Using thesensor information, the controller can move the traveling actuators toaccordingly engage the support mechanisms.

The tracking heliostat arrays disclosed herein optionally include afeedback mechanism to adjust the orientation of the optical elements ina way that increases the amount of solar energy reflected to thecollector. Because the sun moves slowly, a single traveling actuator canbe used in a low duty cycle fashion to serially adjust a large number ofoptical elements.

For example, in one exemplary method, illustrated in the flowchart ofFIG. 7B, a sensor is configured to monitor the amount of electricalcurrent generated by a photovoltaic cell in the collector. The travelingactuator is then moved by the controller to a selected optical element,and adjusts the orientation of the selected optical element in a firstdimension. If the amount of current generated by the photovoltaic cellincreases in response to the adjustment, the optical element is furtheradjusted in the same direction until a decrease is detected. If theamount of current generated by the photovoltaic cell decreases inresponse to the adjustment, the optical element is adjusted in theopposite direction, which should result in a current increase. Theadjustment is then continued until a decrease is detected. The travelingactuator can then repeat the process for the same optical element in asecond dimension, after which the process is repeated for anotherelement in the array. This technique can be modified for otherembodiments wherein the optical elements have other than two degrees offreedom.

More complex orientation algorithms can optionally be used in otherembodiments. For example, the tracking heliostat array optionallyincludes control circuitry capable of calculating the sun's positionbased on the date and time, and orienting the optical elementsaccordingly based on the location where the array is deployed. Asanother example, the tracking heliostat array optionally includescontrol circuitry having instructions with respect to which order theoptical elements should be adjusted in. For example, in one embodiment,the optical elements around the perimeter are reoriented less frequentlythan the optical elements in the center of the array.

Scope of the Invention

While the foregoing detailed description discloses several embodimentsof the present invention, it should be understood that this disclosureis illustrative only and is not limiting of the present invention. Itshould be appreciated that the specific configurations and operationsdisclosed can differ from those described above, and that the methodsdescribed herein can be used in contexts other than tracking heliostatarrays.

1. A tracking heliostat array comprising: a plurality of opticalelements; a frame separated from the optical elements, wherein each ofthe optical elements has an orientation with respect to the frame; aplurality of supports coupled to at least one of the optical elements; aturnbuckle coupled to at least one of the supports and to the frame,wherein rotation of the turnbuckle causes the corresponding support tobe displaced relative to the frame, such that the orientation of theoptical element relative to the frame is adjustable; a travelingactuator configured to rotate at least one of the turnbuckles; and apositioning mechanism supporting the traveling actuator, wherein thepositioning mechanism is configured to move the traveling actuator froma first selected turnbuckle to a second selected turnbuckle.
 2. Thetracking heliostat array of claim 1, wherein the plurality of supportsincludes prongs.
 3. The tracking heliostat array of claim 1, wherein atlest one of the turnbuckles includes a gear configured to engage thetraveling actuator.
 4. The tracking heliostat array of claim 1, whereinthe traveling actuator includes a key, and wherein at least one of theturnbuckles includes an engagement mechanism configured to receive thekey, such that engaging the key with the engagement mechanism androtating the key causes the at least one turnbuckle to rotate.
 5. Thetracking heliostat array of claim 1, wherein the traveling actuatorincludes a key, and wherein at least one of the turnbuckles includes anengagement mechanism configured to receive the key, such that engagingthe key with the engagement mechanism and rotating the key causes the atleast one turnbuckle to rotate, and wherein the engagement mechanismcomprises a four-pronged wheel.
 6. The tracking heliostat array of claim1, wherein the traveling actuator includes a key, and wherein at leastone of the turnbuckles includes an engagement mechanism configured toreceive the key, such that engaging the key with the engagementmechanism and rotating the key causes the at least one turnbuckle torotate; and further comprising an auxiliary motor to engage the key withthe engagement mechanism.
 7. The tracking heliostat array of claim 1,wherein a substantially transparent cover overlays at least one of theoptical elements.
 8. The tracking heliostat array of claim 1, furthercomprising control circuitry configured to operate the travelingactuator to increase a quantity of solar energy reflected from at leastone of the optical elements to a collector.
 9. The tracking heliostatarray of claim 1, further comprising control circuitry configured tooperate the traveling actuator to increase a quantity of solar energyreflected from at least one of the optical elements to a solar cell. 10.The tracking heliostat array of claim 1, wherein at least one of theoptical elements has three degrees of freedom.
 11. The trackingheliostat array of claim 1, further comprising an auxiliary travelingactuator configured to rotate at least one of the turnbuckles.
 12. Thetracking heliostat array of claim 1, wherein at least one of the opticalelements is a mirror.
 13. The tracking heliostat array of claim 1,wherein at least one of the optical elements is a planar mirror.
 14. Thetracking heliostat array of claim 1, wherein at least one of the opticalelements is a reflector.
 15. The tracking heliostat array of claim 1,wherein at least one of the optical elements is a concave reflector. 16.The tracking heliostat array of claim 1, further comprising a collectorpositioned to receive solar energy reflected from at least one of theoptical elements.
 17. The tracking heliostat array of claim 1, furthercomprising a collector positioned to receive solar energy reflected fromat least one of the optical elements, wherein the collector is movablewith respect to the optical elements.
 18. The tracking heliostat arrayof claim 1, further comprising a fixed support prong coupling at leastone of the optical elements to the support frame.
 19. A concentratorapparatus comprising: a plurality of optical elements positionable toconcentrate light; a support structure, wherein each of the opticalelements has an adjustable orientation with respect to the supportstructure; a plurality of adjustment mechanisms, such that actuation of,a selected adjustment mechanism changes the orientation of an opticalelement corresponding to the selected adjustment mechanism; and atraveling actuator configured to sequentially actuate a plurality of theselected adjustment mechanisms.
 20. The concentrator apparatus of claim19, wherein two adjustment mechanisms are associated with one of theoptical elements.
 21. The concentrator apparatus of claim 19, furthercomprising a controller that controls positioning of the travelingactuator with respect to the plurality of optical elements.
 22. Theconcentrator apparatus of claim 19, further comprising computer readablememory that stores the location of the plurality of optical elements.23. The concentrator apparatus of claim 19, wherein the supportstructure is at an incline.
 24. The concentrator apparatus of claim 19,wherein a single adjustment mechanism is associated with one of theoptical elements.
 25. The concentrator apparatus of claim 19, whereinthe adjustment mechanism includes a rod coupled to a first of theoptical elements, wherein the rod is configured to selective push andpull the first optical elements.
 26. The concentrator apparatus of claim19, wherein the adjustment mechanism comprises a turnbuckle having afirst end coupled to the support structure and a second end coupled toone of the optical elements, wherein the turnbuckle first end isrotatable with respect to the turnbuckle second end.
 27. Theconcentrator apparatus of claim 19, wherein the traveling actuatorincludes a key, and wherein at least one of the adjustment mechanismsincludes an engagement mechanism configured to receive the key, suchthat engaging the key with the engagement mechanism and rotating the keyactuates the at least one adjustment mechanism.
 28. The concentratorapparatus of claim 19, wherein at lest one of the optical elements is aplanar mirror.
 29. The concentrator apparatus of claim 19, wherein theplurality of optical elements are arranged in a rectangular array havinga plurality of rows and columns.
 30. The concentrator apparatus of claim19, wherein the plurality of optical elements are arranged in a circulararray.
 31. A method of concentrating solar radiation on a collectorusing a plurality of reflectors, the method comprising: moving atraveling actuator to a first selected one of the plurality ofreflectors; rotating a first turnbuckle corresponding to the firstselected reflector, thereby changing an orientation of the firstselected reflector in a first plane; rotating a second turnbucklecorresponding to the first selected reflector, thereby changing anorientation of the first selected reflector in a second plane orthogonalto the first plane; moving the traveling actuator to a second selectedone of the plurality of reflectors; rotating a third turnbucklecorresponding to the second selected reflector, thereby changing anorientation of the second selected reflector in the first plane; androtating a fourth turnbuckle corresponding to the second selectedreflector, thereby changing an orientation of the second selectedreflector in the second plane.
 32. The method of claim 31, furthercomprising: measuring a quantity of solar energy reflected from theplurality of reflectors to a collector; and adjusting the rotation ofthe first, second, third and fourth turnbuckles to increase the measuredquantity of solar energy.
 33. The method of claim 31, wherein at leastone of the reflectors is a planar mirror.
 34. The method of claim 31,wherein at least one of the reflectors is a concave reflector.
 35. Themethod of claim 31, wherein moving the traveling actuator to the secondselected one of the plurality of reflectors comprises moving thetraveling actuator in a first linear direction and moving the travelingactuator in a second linear direction perpendicular the first lineardirection.
 36. The method of claim 31, wherein moving the travelingactuator to the second selected one of the plurality of reflectorscomprises simultaneously moving the traveling actuator in a first lineardirection and in a second linear direction perpendicular the firstlinear direction.
 37. The method of claim 31, wherein moving thetraveling actuator to the second selected one of the plurality ofreflectors comprises moving the traveling actuator in an angulardirection and in a radial direction.
 38. A method of concentratingoptical energy onto a collector, the method comprising: positioning atraveling actuator to engage a first optical element; moving the firstoptical element from a first orientation to a second orientation usingthe traveling actuator, wherein the first optical element reflects moreoptical energy onto a collector when positioned in the secondorientation as compared to the first orientation; positioning thetraveling actuator to engage a second optical element; and moving thesecond optical element from a first orientation to a second orientationusing the traveling actuator, wherein the second optical elementreflects more optical energy onto the collector when positioned in thesecond orientation as compared to the first orientation.
 39. The methodof claim 38, wherein the traveling actuator engages at least one of thefirst and second optical elements using a magnet.
 40. The method ofclaim 38, wherein at least one of the optical elements is a planarmirror.
 41. The method of claim 38, wherein at lest one of the opticalelements includes a lens.
 42. The method of claim 38, wherein moving thefirst optical element from the first orientation to the secondorientation comprises rotating a turnbuckle that is coupled to the firstoptical element and a support frame underlying the plurality of opticalelements.
 43. The method of claim 38, wherein at least one of theoptical elements has three degrees of freedom.
 44. The method of claim38, wherein at lest one of the optical elements has two degrees offreedom.
 45. The method of claim 38, wherein the collector is a solarcell.
 46. The method of claim 38, wherein the collector is a Stirlingengine.
 47. A concentrator system comprising: a first optical elementtiltable with respect to at least one axis via a first adjustmentstructure; a second optical element tiltable with respect to at leastone axis via a second adjustment structure, wherein the second opticalelement is tiltable independently of the first optical element; and atraveling actuator configured to travel to engage the first adjustmentstructure to tilt the first optical element to a first desiredorientation, and to travel to engage the second adjustment structure totilt the second optical element to a second desired orientation.
 48. Theconcentrator system as defined in claim 47, wherein the first opticalelement is a reflector.
 49. The concentrator system as defined in claim47, further comprising a solar cell, wherein the first optical elementand the second optical element are tiltable to concentrate sunlight onthe solar cell.
 50. The concentrator system as defined in claim 47,further comprising a receiver, wherein the first optical element and thesecond optical element are tiltable to concentrate sunlight on thereceiver.
 51. The concentrator system as defined in claim 47, furthercomprising a solar cell, and wherein the first optical element and thesecond optical element are tiltable to concentrate sunlight on the solarcell.
 52. The concentrator system as defined in claim 47, wherein thefirst adjustment structure includes a receiving portion configured toreceive a portion of the traveling actuator.
 53. The concentrator systemas defined in claim 47, wherein the first adjustment structure includesa gear configured to engage the traveling actuator.
 54. The concentratorsystem as defined in claim 47, wherein the first adjustment structureincludes a screw mechanism rotatable by the traveling actuator.
 55. Theconcentrator system as defined in claim 47, wherein the first opticalelement is positioned on a first side of a receiver and the secondoptical element is position on an opposite side of the receiver.
 56. Theconcentrator system as defined in claim 47, wherein the first actuatorincludes a first motor that moves the traveling actuator along a firstaxis and a second motor that move the actuator along a second axis. 57.The concentrator system as defined in claim 47, wherein the firstactuator includes a first motor configured to move the travelingactuator along a first axis and a second motor configured to separatelyengage the first and second adjustment mechanism.
 58. The concentratorsystem as defined in claim 47, further comprising control circuitryconfigured to operate the traveling actuator to increase a quantity ofsolar energy reflected from at least one of the optical elements to areceiver.
 59. The concentrator system as defined in claim 47, furthercomprising computer readable memory configured to store positioninformation corresponding to the first and second adjustment structures.60. The concentrator system as defined in claim 47, further comprising asensor configured to locate the first and second adjustment structures.